A facile synthesis of Cu(II) diethyldithiocarbamate from monovalent copper-cysteamine and disulfiram

Abstract

An efficient, atom-economic synthesis of Cu(II) diethyldithiocarbamate from a monovalent copper-cysteamine and disulfiram was developed. • An efficient and atom-economic synthesis of Cu(DDC)2 from DSF and monovalent copper cysteamine (CuCy) is reported. • The chemical structure, proposed reaction mechanism and the optimal reaction conditions were investigated. • The photochemical reactions of Cu(DDC) 2 in five solvents and the possible reaction mechanism were discussed. The copper(II) diethyldithiocarbamate (Cu(DDC) 2 ) complex prepared from disulfiram and Cu(II) species has shown excellent anticancer activity. However, general synthetic methods largely rely on tedious procedures and limited reaction types with undesirable by-products. In this paper, we reported an efficient and atom-economic synthesis of Cu(DDC) 2 from disulfiram and monovalent copper cysteamine (Cu(I)Cy) via a one-step oxidation–reduction reaction. Cu(DDC) 2 was fully characterized by nuclear magnetic resonance (NMR), mass spectrometry (MS), infrared spectroscopy (IR), scanning electron microscope (SEM), X-ray diffraction (XRD), ultraviolet and visible (UV–Vis) spectrophotometry, X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR) and single crystal X-ray diffraction. The proposed reaction mechanism and the effect of reaction conditions on the Cu(DDC) 2 synthesis were investigated. The photochemical reactions of Cu(DDC) 2 was studied in acetone, DMF, toluene, CCl 4 , CHCl 3 under 254, 365 nm alone or combined 254 & 365 nm irradiation based on UV–vis and EPR measurements. The photolysis rate followed in this order: CCl 4 > CHCl 3 > DMF > toluene > acetone. The final photolysis products in CHCl 3 were DSF and Cu 2 (DDC) 2 Cl 2 .